The present invention relates to an active-matrix-type liquid crystal display panel for applying driving signals to pixel electrodes through switching elements and performing a display by an electric potential difference between an opposing electrode and the pixel electrodes. The present invention also relates to a method of inspecting such an active-matrix-type liquid crystal display panel.
A conventional liquid crystal display device includes a plurality of pixel electrodes arranged in a matrix form, an opposing electrode as a common electrode provided so as to face the pixel electrodes, and liquid crystal as display medium provided between the pixel electrode and the opposing electrode. Such a liquid crystal display device performs a display in the following manner. Namely, an electric potential is selectively written into the pixel electrode, and an optical modulation of the liquid crystal provided between the pixel electrode and the opposing electrode is taken place by the electric potential difference between the pixel electrode and the opposing electrode, and visually recognized as a display pattern.
As a method of driving the pixel electrode, a so-called active matrix driving method is known. In this method, the pixel electrodes provided in the matrix form are each connected to switching elements, and each of the pixel electrodes is driven by the switching element. General switching elements are a TFT (thin film transistor), a MIM (metal-insulator-metal) element, etc.
An active-matrix-type liquid crystal display panel provided in an active-matrix-type liquid crystal display device includes an active matrix substrate and an opposing substrate. In the active matrix substrate, a plurality of scanning lines and a plurality of data lines are provided on a transparent insulating substrate so as to cross each other, and a pixel electrode and a switching element for driving the pixel electrode are formed at each intersection of the scanning line and the data line. In the opposing substrate, an opposing electrode is formed on a transparent insulating substrate. The active matrix substrate and the opposing substrate are provided with alignment films on their surfaces where the two substrates face each other, and adhered to each other with a liquid crystal layer therebetween.
FIG. 28 shows the structure of each pixel of the active matrix substrate using the TFT as the switching element. A gate electrode of a pixel TFT 1 is connected to a scanning line 2, and the pixel TFT 1 is driven by a scanning signal inputted to the scanning line 2. A source electrode of the pixel TFT 1 is connected to a data line 3, and a display signal is inputted to the data line 3. A drain electrode of the pixel TFT 1 is connected to a pixel electrode 14 and one terminal of an auxiliary capacity, through an auxiliary capacity electrode 28. The other terminal of the auxiliary capacity is connected to an auxiliary capacity wiring 4, and then connected to the opposing electrode on the opposing substrate when a liquid crystal cell is constructed. The pixel TFT 1 and the pixel electrode 14 are provided in the matrix form on the insulating substrate.
FIG. 29 shows one example of the structure of the cross section of the active matrix substrate. A gate electrode 8, a gate insulating film 9, a semiconductor layer 10, a n+-Si layer 11 to be the source and drain electrodes, a metal layer 12 to be the data line 3, an interlayer insulating film 13, and a transparent conductive layer to be the pixel electrode 14 are formed in this order on an insulating substrate 7. The pixel electrode 14 is connected to the drain electrode of the pixel TFT 1 through a contact hole 15 piercing the interlayer insulating film 13, specifically through the auxiliary capacity electrode 28.
In the structure shown in FIG. 29, the interlayer insulating film 13 is formed between the scanning line 2 (the same layer as the gate electrode 8) and the pixel electrode 14 and between the data line 3 and the pixel electrode 14. Therefore, the pixel electrode 14 can be arranged to overlap the data line 3. It is known that such an arrangement can improve the aperture ratio, and reduce an alignment defect of liquid crystal by shielding the electric field resulting from the data line 3.
Next, the process thereafter will be explained with reference to FIG. 30. FIG. 30 is a schematic plan view of a conventional active-matrix-type liquid crystal display device. This view shows the state after a large substrate is divided into cells, each of which corresponds to a display device. In the actual process, the cells are often produced in the state where several cells are arranged in rows and columns.
On a viewing area (within the two-dot chain lines) 17 of a completed active matrix substrate 50, an alignment film of the polyimide family is deposited, and the alignment function is added by a treatment such as rubbing. In an opposing substrate 51, a transparent opposing electrode (not shown) such as ITO (Indium Tin Oxide) is deposited, and then the part corresponding to the viewing area 17 is subjected to the same treatment.
A sealing material (not shown) is applied to the surrounding section of the liquid crystal display panel except for a liquid crystal injection port in such a manner as to surround the panel by the printing method, etc. Further, a conductive material 19 is attached onto an opposing-substrate-use signal input terminal 27 on the active matrix substrate 50. Thereafter, a spacer (not shown) for keeping the cell thickness of the liquid crystal layer uniform is sprayed. Then, the active matrix substrate 50 is adhered to the opposing substrate 51, and the sealing material is fixed by adding heat.
Thereafter, liquid crystal is injected through the liquid crystal injection port, and the liquid crystal injection port is closed with an end-sealing material, thereby completing the panel section of the liquid crystal display device. Then, packaging members such as a source driver 20a for applying a display signal to each data line 3, a gate driver 20b for applying a scanning signal to each scanning line 2, a control circuit (not shown), and a backlight (not shown) are installed, thereby completing the liquid crystal display device. Note that the liquid crystal display device shown in FIG. 30 is not provided with the auxiliary capacity wiring 4.
By the way, the inspection of such a liquid crystal display device usually includes an optical inspection performed in each step of the process, an electrical inspection performed in the step where the active matrix substrate is completed, and a dynamic operating inspection and the electrical inspection, performed at the time when the panel section on which the packaging members such as the driver are not yet installed is completed.
Such inspections are performed so as to prevent materials and operations from being wasted by leaving defective parts in the subsequent process. When a deficiency exists in a device, the device is discarded at this time or repaired by means of laser, etc.
However, with the recent improvement of the production technique, the liquid crystal display panel has achieved ever higher definition, and accordingly a higher technique has been required also in the inspection process.
Specifically, since the terminals for inputting the signals to the data lines 3 and the scanning lines 2 are installed with increasingly smaller pitches, when supplying the signals by bringing the respective terminals into electric contact with pins, a prober of extremely high definition and high cost must be prepared. In addition, there is a case where existence of fine dust on the terminals in the inspection interferes with normal dynamic operations, and the defective inspection is recognized as a deficiency of the panel by mistake. In order to avoid such a case, the inspection must be performed in very clean environments. Consequently, a rise in the total cost has been unavoidable.
In order to realize an easier inspection, the liquid crystal display device shown in FIG. 30 has the following structure. Specifically, this liquid crystal display device includes inspection-use display signal lines 52a, 52b and 52c for connecting the data lines 3 which supply the same signal in the inspection with each other, and inspection-use scanning signal lines 53a and 53b for connecting the scanning lines 2 which supply the same signal in the inspection with each other. The inspection-use display signal lines 52a, 52b, 52c and the inspection-use scanning signal lines 53a, 53b are cut off by dicing the substrate along cutting lines L after the inspection or electrically separated by means of laser cutting, etc. in general (for example, as disclosed in the Japanese Publication of Unexamined Patent Application No. 005481/1995 (Tokukaihei 07-005481; published on Jan. 10, 1995)).
However, this method produces another problem that the number of processes is increased because of the cutting process. Moreover, defective units may be newly generated due to fragments of the wiring pattern and scrap pieces of glass, produced by cutting the substrate. In addition, the area to be cut on the large substrate is wasted in the case of dicing, which is disadvantageous in the number of panels to be obtained.
Further, cutting the substrate may produce a static electricity, thereby possibly causing the switching element to be broken by the static electricity.
For example, a method for avoiding the increase of the number of processes for cutting the substrate was devised. In this method, instead of completely bringing the lines for sending the same signal into electric conduction, switching elements such as TFTs are provided for the lines, and signals for switching on the switching elements are supplied as necessary in the inspection, thereby achieving the same effect as the method where the lines are connected to each other.
For example, the method disclosed in Japanese Publication of Unexamined Patent Application No. 142499/1991 (Tokukaihei 03-142499; published on Jun. 18, 1991) is one of the methods in which the signals are supplied to the scanning lines and the data lines through the switching elements. In this method, signals are subsequently supplied through the switching elements in the state where the substrate is still a large substrate, the respective pixels are charged, and the signals are subsequently read out through the switching elements, thereby electrically obtaining defect information in the screen.
Since this method enables the detection of a defective active matrix substrate in the process before adhering the active matrix substrate to the opposing substrate, it is advantageous in that the processes are not wasted. However, since it is necessary to accurately readout the extremely small electric signals especially when detecting dot defects, this method has many difficult problems including the design of a sense amplifier, the circuit sequence, and the optimization of the balance between the time constant and the readout time of the pixel TFT. In addition, especially in the detection of display unevenness and a low lit defect, the result obtained by the electrical inspection was much different from that of the inspection where the display is actually performed.
In order to solve the problems, the liquid crystal display panel disclosed in Japanese Publication of Unexamined Patent Application No. 333275/1995 (Tokukaihei 07-333275; published on Dec. 22, 1995) is arranged so that the signals are supplied through the switching elements in the same manner, and the dynamic operating inspection can be performed as conventionally done.
FIG. 31 shows the arrangement of the liquid crystal display panel disclosed in the above publication (Tokukaihei 07-333275). In this structure, five terminals Z1 to Z5 provided near the edge section on the surface of the panel are connected to inspection-use signal lines x1 to x7. Further, TFTs 66 as the switching elements are individually formed for the respective scanning lines 2 between the signal lines x1, x2, x3 and the scanning lines 2, while TFTs 67 are individually formed for the respective data lines 3 between the signal lines x4, x5 and the data lines 3. The signals inputted from the terminals z1 to z5 are sent to pixel sections 60 through the respective TFTs 67 and 66.
With this arrangement, when performing the inspection of the liquid crystal display panel, the panel can be driven by only inputting the inspection signals to the terminals z1 to z5, without supplying the inspection signals to the terminals p of the scanning lines 2 and to the terminals q of the data lines 3 line by line. It is thus possible to save the efforts in the inspection.
However, the structure disclosed in the above publication (Tokukaihei 07-333275) has the following drawbacks in the inspection.
Specifically, as shown in FIG. 31, the inspection-use signal line for supplying the signals to the respective data lines 3 is only x4. Thus, the line defects and the dot defects are detected by performing the monochromatic display of black or white in this inspection.
However, due to the recent improvement of the production technique, the display devices have been required to achieve higher display quality, and strict standards have been provided for the dark defect as well as the luminous dot. The dark defect has several types, and the most frequent one in the normally white method is the defect caused when a leakage occurs between a pixel electrode and the data line 3 which should not supply the signal to the pixel electrode (in general, the data line 3 which supplies the signal to an adjacent pixel). Such a defect is detected when performing the monochromatic display.
In the conventional structure according to the above publication, it is impossible to detect such a dark defect, because different signals cannot be supplied to the adjacent data lines. In recent years when display devices have achieved ever higher definition, with the densification of the pattern and the increase of the pixel number, the defect of this type cannot be neglected.
Further, in the conventional structure disclosed in the above publication, since different signals cannot be supplied to the adjacent data lines, the leakage between the data lines 3 cannot be detected.
In order to detect the leakage defect between the data lines 3, the electrical inspection as well as the visual inspection must be performed. One reason for this is that the line defect is much more serious than the dot defect. Another reason is that there is a danger that the defect which was not detected in the visual inspection due to the variation with time of the leakage part and the temperature characteristics of the leakage current may cause a problem on the market.
In addition, like the liquid crystal display panel disclosed in the above publication (Tokukaihei 07-333275), in the case where the inspection-use signals are supplied to the data lines or the scanning lines through the switching elements, the data lines and the scanning lines must be electrically independent of each other after the liquid crystal display panel is completed. Therefore, when a leakage is caused in the switching element, a deficiency in the display and a malfunction may occur.
Further, when a static electricity enters the wiring for supplying the inspection-use signals to the data lines and the scanning lines through the switching elements, an electrical breakdown may occur between the gate and drain or between the gate and source of the switching elements due to a high voltage, thereby possibly causing the leakage defect mentioned above.
There has conventionally been an active matrix substrate in which a static-electricity breakdown of the substrate is prevented by connecting the data lines or the scanning lines with a resistive element so as to let the static electricity generated in a specific line escape into another line, thereby dispersing the static electricity. However, such an active matrix substrate has such a problem that when supplying the signals to the data lines or the scanning lines through the inspection-use wiring in inspecting the active matrix substrate, a voltage applied to the data lines or the scanning liens is decreased by a voltage drop in the inspection-use wiring.
In addition, the inspection efficiency is low, because the inspection is performed in such a manner that a plurality of liquid crystal display panels are produced in a state of being a large substrate, the large substrate is cut into individual liquid crystal display panels, and the inspection is performed for each liquid crystal display panel.
The present invention simultaneously solves the problems of the above-mentioned prior art. A first object of the present invention is to achieve an inspection with higher accuracy by performing a monochromatic display, without increasing unnecessary regions and increasing processes and defective units by cutting such regions, so as to prevent the outflow of the defective units and reduce the production cost.
A second object of the present invention is to prevent the decrease of the yield and the decrease of the display quality of the liquid crystal display panel caused by inspection-use switching elements in an active-matrix-type liquid crystal display panel arranged so that wiring for supplying inspection-use signals to data lines or scanning lines are connected to the data lines or the scanning lines through the inspection-use switching elements.
A third object of the present invention is to prevent the voltage applied to the data lines or the scanning lines from being decreased by a voltage drop in the inspection-use wiring for supplying the inspection-use signals to the data lines or the scanning lines when inspecting the liquid crystal display panel, in an active-matrix-type liquid crystal display panel including a resistive element between the data lines or the scanning lines so as to avoid the static-electricity breakdown.
A fourth object of the present invention is to inspect a plurality of liquid crystal display panels at the same time so as to significantly improve the inspection efficiency.
In order to achieve the first object, an active-matrix-type liquid crystal display panel in accordance with one embodiment of the present invention is characterized in including:
an active matrix substrate including on an insulating substrate: a plurality of pixel electrodes; pixel switching elements individually connected to the pixel electrodes; and a plurality of scanning lines and a plurality of data lines, provided in a lattice form, for driving the pixel electrodes through the pixel switching elements;
an opposing substrate including a common electrode, the opposing substrate being adhered to the active matrix substrate with a liquid crystal layer therebetween;
data-line inspection-use switching elements, individually connected to the plurality of data lines, for controlling a supply of an inspection-use display signal;
an inspection-use display signal line for supplying an inspection-use display signal to the data lines through the data-line inspection-use switching elements, the inspection-use display signal line being a common inspection-use display signal line provided for the data-line inspection-use switching elements; and
a plurality of data-line inspection-use control signal lines for inputting control signals for switching on/off the data-line inspection-use switching elements, the plurality of data-line inspection-use control signal lines being provided for the data-line inspection-use switching elements so that different control signals are inputted to adjacent data lines.
It is thus possible to provide a liquid crystal display panel enabling a recognition of a leakage defect between the signal lines and a visual detection of a leakage between the data lines without increasing the number of processes.
Further, in a method of inspecting the active-matrix-type liquid crystal display panel, a color display is performed by sequentially switching control signals supplied to a plurality of data-line inspection-use control signal lines, while supplying the inspection-use display signal to the inspection-use display signal line. Therefore, the color display in the inspection is enabled without increasing the number of processes. As a result, in addition to the leakage defect between the signal lines, a leakage between the data lines and a leakage defect between adjacent pixels can be visually detected easily.
In order to achieve the first object, an active-matrix-type liquid crystal display panel in accordance with another embodiment of the present invention is characterized in including:
an active matrix substrate including on an insulating substrate: a plurality of pixel electrodes; pixel switching elements individually connected to the pixel electrodes; and a plurality of scanning lines and a plurality of data lines, provided in a lattice form, for driving the pixel electrodes through the pixel switching elements;
an opposing substrate including a common electrode, the opposing substrate being adhered to the active matrix substrate with a liquid crystal layer therebetween;
data-line inspection-use switching elements, individually connected to the plurality of data lines, for controlling a supply of an inspection-use display signal;
a data-line inspection-use control signal line for inputting control signals for switching on/off the data-line inspection-use switching elements, the data-line inspection-use control signal line being a common data-line inspection-use control signal line provided for the data-line inspection-use switching elements; and
a plurality of inspection-use display signal lines for supplying inspection-use display signals to the data lines through the data-line inspection-use switching elements, the plurality of inspection-use display signal lines being provided for the data-line inspection-use switching elements so that different display signals are inputted to adjacent data lines.
It is thus possible to provide a liquid crystal display panel without increasing the number of processes, where a leakage defect between the signal lines can be recognized, a leakage between the data lines can be visually detected, and a leakage defect between signal lines, which is not to be visually detected, can be electrically detected.
In addition, in a method of inspecting the active-matrix-type liquid crystal display panel, a color display is performed by sequentially switching the inspection-use display signals supplied to a plurality of inspection-use display signal lines, while supplying the control signal to the data-line inspection-use control signal line. Therefore, the color display in the inspection is enabled without increasing the number of processes. As a result, a leakage between the data lines and a leakage defect between adjacent pixels can be visually detected easily, and a leakage defect between signal lines and data lines, which is not to be visually detected, can be electrically detected.
In order to achieve the second object, an active-matrix-type liquid crystal display panel in accordance with one embodiment of the present invention is characterized in including:
(a) an active matrix substrate including on an insulating substrate: a plurality of pixel electrodes; pixel switching elements individually connected to the pixel electrodes; and a plurality of scanning lines and a plurality of data lines, provided in a lattice form, for driving the pixel electrodes through the pixel switching elements;
(b) an opposing substrate including a common electrode, the opposing substrate being adhered to the active matrix substrate with a liquid crystal layer therebetween;
characteristics (c) and/or characteristics (d).
The characteristics (c) includes:
data-line inspection-use switching elements, individually connected to the plurality of data lines, for controlling a supply of an inspection-use display signal;
an inspection-use display signal line, provided for the data-line inspection-use switching elements, for supplying an inspection-use display signal to the data lines through the data-line inspection-use switching elements; and
a data-line inspection-use control signal line, provided for the data-line inspection-use switching elements, for inputting control signals for switching on/off the data-line inspection-use switching elements;
wherein a voltage for switching off the data-line inspection-use switching elements is applied to the data-line inspection-use control signal line while the liquid crystal display panel is driven.
The characteristics (d) includes:
scanning-line inspection-use switching elements, individually connected to the plurality of scanning lines, for controlling a supply of an inspection-use scanning signal;
an inspection-use scanning signal line, provided for the scanning-line inspection-use switching elements, for supplying an inspection-use scanning signal to the scanning lines through the scanning-line inspection-use switching elements;
a scanning-line inspection-use control signal line, provided for the scanning-line inspection-use switching elements, for inputting control signals for switching on/off the scanning-line inspection-use switching elements,
wherein a voltage for switching off the scanning-line inspection-use switching elements is applied to the scanning-line inspection-use control signal line while the liquid crystal display panel is driven.
Thus, when the liquid crystal display panel is driven, a voltage for switching off the inspection-use switching elements is applied to the data-line inspection-use control signal line and/or the scanning-line inspection-use control signal line. Therefore, a malfunction can be prevented when the liquid crystal display panel is driven.
An active-matrix-type liquid crystal display panel in accordance with another embodiment of the present invention is characterized in including:
(a) an active matrix substrate including on an insulating substrate: a plurality of pixel electrodes; pixel switching elements individually connected to the pixel electrodes; and a plurality of scanning lines and a plurality of data lines, provided in a lattice form, for driving the pixel electrodes through the pixel switching elements;
(b) an opposing substrate including a common electrode, the opposing substrate being adhered to the active matrix substrate with a liquid crystal layer therebetween;
characteristics (c) and/or characteristics (d).
The characteristics (c) includes:
data-line inspection-use switching elements, individually connected to the plurality of data lines, for controlling a supply of an inspection-use display signal;
an inspection-use display signal line, provided for the data-line inspection-use switching elements, for supplying an inspection-use display signal to the data lines through the data-line inspection-use switching elements;
a data-line inspection-use control signal line, provided for the data-line inspection-use switching elements, for inputting control signals for switching on/off the data-line inspection-use switching elements; and
a resistive element between a signal input point of the data-line inspection-use control signal line and the data-line inspection-use switching elements.
The characteristics (d) includes:
scanning-line inspection-use switching elements, individually connected to the plurality of scanning lines, for controlling a supply of an inspection-use scanning signal;
an inspection-use scanning signal line, provided for the scanning-line inspection-use switching elements, for supplying an inspection-use scanning signal to the scanning lines through the scanning-line inspection-use switching elements;
a scanning-line inspection-use control signal line, provided for the scanning-line inspection-use switching elements, for inputting control signals for switching on/off the scanning-line inspection-use switching elements; and
a resistive element between a signal input point of the scanning-line inspection-use control signal line and the scanning-line inspection-use switching elements.
A resistive element is provided between a signal input terminal of the data-line inspection-use control signal line and the inspection-use switching elements to which the data-line inspection-use control signal line is connected, and/or between a signal input terminal of the scanning-line inspection-use control signal line and the inspection-use switching elements to which the scanning-line inspection-use control signal line is connected. It is thus possible to prevent the inspection-use switching elements from being broken by the static electricity flowing through the control signal lines without a hitch in the inspection.
An active-matrix-type liquid crystal display panel in accordance with another embodiment of the present invention is characterized in including:
(a) an active matrix substrate including on an insulating substrate: a plurality of pixel electrodes; pixel switching elements individually connected to the pixel electrodes; and a plurality of scanning lines and a plurality of data lines, provided in a lattice form, for driving the pixel electrodes through the pixel switching elements;
(b) an opposing substrate including a common electrode, the opposing substrate being adhered to the active matrix substrate with a liquid crystal layer therebetween;
characteristics (c) and/or characteristics (d).
The characteristics (c) includes:
data-line inspection-use switching elements for controlling a supply of an inspection-use display signal, the data-line inspection-use switching elements being individually connected to the plurality of data lines and provided on a side opposite to a region where an external circuit for driving the data lines is provided;
an inspection-use display signal line, provided for the data-line inspection-use switching elements, for supplying an inspection-use display signal to the data lines through the data-line inspection-use switching elements; and
a data-line inspection-use control signal line, provided for the data-line inspection-use switching elements, for inputting control signals for switching on/off the data-line inspection-use switching elements.
The characteristics (d) includes:
scanning-line inspection-use switching elements for controlling a supply of an inspection-use scanning signal, the scanning-line inspection-use switching elements being individually connected to the plurality of scanning lines and provided on a side opposite to a region where an external circuit for driving the scanning lines is provided;
an inspection-use scanning signal line, provided for the scanning-line inspection-use switching elements, for supplying an inspection-use scanning signal to the scanning lines through the scanning-line inspection-use switching elements; and
a scanning-line inspection-use control signal line, provided for the scanning-line inspection-use switching elements, for inputting control signals for switching on/off the scanning-line inspection-use switching elements.
The inspection-use switching elements are provided on the opposite side of the external circuit. Therefore, a margin in space is secured for pattern forming in the vicinity of the driver circuit, and the inspection-use switching elements can be cut off as necessary when the inspection-use switching elements are broken.
An active-matrix-type liquid crystal display panel in accordance with another embodiment of the present invention is characterized in including:
(a) an active matrix substrate including on an insulating substrate: a plurality of pixel electrodes; pixel switching elements individually connected to the pixel electrodes; and a plurality of scanning lines and a plurality of data lines, provided in a lattice form, for driving the pixel electrodes through the pixel switching elements;
(b) an opposing substrate including a common electrode, the opposing substrate being adhered to the active matrix substrate with a liquid crystal layer therebetween;
characteristics (c) and/or characteristics (d).
The characteristics (c) includes:
data-line inspection-use switching elements for controlling a supply of an inspection-use display signal, the data-line inspection-use switching elements being shaded and individually connected to the plurality of data lines;
an inspection-use display signal line, provided for the data-line inspection-use switching elements, for supplying an inspection-use display signal to the data lines through the data-line inspection-use switching elements; and
a data-line inspection-use control signal line, provided for the data-line inspection-use switching elements, for inputting control signals for switching on/off the data-line inspection-use switching elements.
The characteristics (d) includes:
scanning-line inspection-use switching elements for controlling a supply of an inspection-use scanning signal, the scanning-line inspection-use switching elements being shaded and individually connected to the plurality of scanning lines;
an inspection-use scanning signal line, provided for the scanning-line inspection-use switching elements, for supplying an inspection-use scanning signal to the scanning lines through the scanning-line inspection-use switching elements; and
a scanning-line inspection-use control signal line, provided for the scanning-line inspection-use switching elements, for inputting control signals for switching on/off the scanning-line inspection-use switching elements.
Since the inspection-use switching elements are shaded, a leakage current is reduced when the elements are switched off. Therefore, a malfunction caused when the liquid crystal display panel is driven can be prevented, and the problem in reliability can be eliminated.
Further, in a method of inspecting the active-matrix-type liquid crystal display panel, when inspecting the liquid crystal display panel, the data-line inspection-use switching elements and/or the scanning-line inspection-use switching elements are exposed to light. Therefore, the resistance value of the inspection-use switching elements can be lowered only in the inspection, and a satisfactory inspection can be performed.
An active-matrix-type liquid crystal display panel in accordance with another embodiment of the present invention is characterized in including:
(a) an active matrix substrate including on an insulating substrate: a plurality of pixel electrodes; pixel switching elements individually connected to the pixel electrodes; and a plurality of scanning lines and a plurality of data lines, provided in a lattice form, for driving the pixel electrodes through the pixel switching elements;
(b) an opposing substrate including a common electrode, the opposing substrate being adhered to the active matrix substrate with a liquid crystal layer therebetween;
characteristics (c) and/or characteristics (d).
The characteristics (c) includes:
data-line inspection-use switching elements for controlling a supply of an inspection-use display signal, the data-line inspection-use switching elements being individually connected to the plurality of data lines, and having a higher threshold value than the pixel switching element when the liquid crystal display panel is driven;
an inspection-use display signal line, provided for the data-line inspection-use switching elements, for supplying an inspection-use display signal to the data lines through the data-line inspection-use switching elements; and
a data-line inspection-use control signal line, provided for the data-line inspection-use switching elements, for inputting control signals for switching on/off the data-line inspection-use switching elements.
The characteristics (d) includes:
scanning-line inspection-use switching elements, for controlling a supply of an inspection-use scanning signal, the scanning-line inspection-use switching elements being individually connected to the plurality of scanning lines, and having a higher threshold value than the pixel switching element when the liquid crystal display panel is driven;
an inspection-use scanning signal line, provided for the scanning-line inspection-use switching elements, for supplying an inspection-use scanning signal to the scanning lines through the scanning-line inspection-use switching elements; and
a scanning-line inspection-use control signal line, provided for the scanning-line inspection-use switching elements, for inputting control signals for switching on/off the scanning-line inspection-use switching elements.
When actually driving the liquid crystal display panel after packaging is completed, the threshold value of the inspection-use switching elements is set higher than that of the pixel switching elements. Therefore, a leakage in the inspection-use switching elements can be prevented. Further, after inspecting the liquid crystal display panel, the threshold value of the inspection-use switching elements can be shifted in a positive direction by applying a positive voltage to the gate electrodes of the inspection-use switching elements. In this case, applying a heat at the same time as the application of the positive voltage is preferable, because it enhances the shift of the threshold value in the threshold value.
In order to achieve the third object, an active-matrix-type liquid crystal display panel in accordance with one embodiment of the present invention is characterized in including:
(a) an active matrix substrate including on an insulating substrate: a plurality of pixel electrodes; pixel switching elements individually connected to the pixel electrodes; and a plurality of scanning lines and a plurality of data lines, provided in a lattice form, for driving the pixel electrodes through the pixel switching elements;
(b) an opposing substrate including a common electrode, the opposing substrate being adhered to the active matrix substrate with a liquid crystal layer therebetween;
characteristics (c) and/or characteristics (d).
The characteristics (c) includes:
a plurality of inspection-use display signal lines for supplying inspection-use display signals, the plurality of inspection-use display signal lines being provided for the plurality of data lines so that different display signals are inputted to adjacent data lines; and
a resistive element provided between the adjacent data lines;
wherein rd/(n/k) greater than 8R is satisfied where rd is a resistance value of each resistive element, n is a number of the data lines, k is a number of the inspection-use display signal lines, and R is a resistance value of the inspection-use display signal lines.
The characteristics (d) includes:
a plurality of inspection-use scanning signal lines for supplying an inspection-use scanning signal, the inspection-use scanning signal lines being provided for the plurality of scanning lines so that different scanning signals are inputted to adjacent scanning lines; and
a resistive element provided between the adjacent scanning lines;
wherein rd/(n/k) greater than 8R is satisfied where rd is a resistance value of each resistive element, n is a number of the scanning lines, k is a number of the inspection-use scanning signal lines, and R is a resistance value of the inspection-use scanning signal lines.
Therefore, the voltage drop produced in the inspection-use display signal line and/or the inspection-use scanning signal line is reduced, and a voltage not less than 80% of the voltage applied to the input terminal of the inspection-use wiring can be applied to the data lines or scanning lines. Namely, a sufficient applied voltage can be achieved.
An active-matrix-type liquid crystal display panel in accordance with another embodiment of the present invention is characterized in including:
(a) an active matrix substrate including on an insulating substrate: a plurality of pixel electrodes; pixel switching elements individually connected to the pixel electrodes; and a plurality of scanning lines and a plurality of data lines, provided in a lattice form, for driving the pixel electrodes through the pixel switching elements;
(b) an opposing substrate including a common electrode, the opposing substrate being adhered to the active matrix substrate with a liquid crystal layer therebetween;
characteristics (c) and/or characteristics (d).
The characteristics (c) includes:
data-line inspection-use switching elements, individually connected to the plurality of data lines, for controlling a supply of an inspection-use display signal;
a data-line inspection-use control signal line for inputting control signals for switching on/off the data-line inspection-use switching elements, the data-line inspection-use control signal line being a common data-line inspection-use control signal line provided for the data-line inspection-use switching elements;
a plurality of inspection-use display signal lines for supplying inspection-use display signals to the data lines through the data-line inspection-use switching elements, the plurality of inspection-use display signal lines being provided for the data-line inspection-use switching elements so that different display signals are inputted to adjacent data lines; and
a resistive element provided between adjacent data lines;
wherein rd greater than 8Rxc2x7(n/k)+16rtr is satisfied where rd is a resistance value of each resistive element, rtr is a resistance value of each data-line inspection-use switching element, n is a number of the data lines, k is a number of the inspection-use display signal lines, and R is a resistance value of the inspection-use display signal lines.
The characteristics (d) includes:
scanning-line inspection-use switching elements, individually connected to the plurality of scanning lines, for controlling a supply of an inspection-use scanning signal;
a scanning-line inspection-use control signal line for inputting control signals for switching on/off the scanning-line inspection-use switching elements, the scanning-line inspection-use control signal line being a common scanning-line inspection-use control signal line provided for the scanning-line inspection-use switching elements;
a plurality of inspection-use scanning signal lines for supplying inspection-use scanning signals to the scanning lines through the scanning-line inspection-use switching elements, the inspection-use scanning signal line being provided for the scanning-line inspection-use switching elements so that different scanning signals are inputted to adjacent scanning lines; and
a resistive element provided between the adjacent scanning lines;
wherein rd greater than 8Rxc2x7(n/k)+16rtr is satisfied where rd is a resistance value of each resistive element, rtr is a resistance value of each scanning-line inspection-use switching element, n is a number of the scanning lines, k is a number of the inspection-use scanning signal lines, and R is a resistance value of the inspection-use scanning signal lines.
Therefore, the voltage drop produced in the inspection-use display signal line and/or the inspection-use scanning signal line is reduced, and a voltage not less than 80% of the voltage applied to the input terminal of the inspection-use wiring can be applied to the data lines or scanning lines. Namely, a sufficient applied voltage can be achieved.
An active-matrix-type liquid crystal display panel in accordance with another embodiment of the present invention is characterized in including:
(a) an active matrix substrate including on an insulating substrate: a plurality of pixel electrodes; pixel switching elements individually connected to the pixel electrodes; and a plurality of scanning lines and a plurality of data lines, provided in a lattice form, for driving the pixel electrodes through the pixel switching elements;
(b) an opposing substrate including a common electrode, the opposing substrate being adhered to the active matrix substrate with a liquid crystal layer therebetween;
characteristics (c) and/or characteristics (d).
The characteristics (c) includes:
a plurality of inspection-use display signal lines for supplying inspection-use display signals, the inspection-use display signal lines being provided for the plurality of data lines so that different display signals are inputted to adjacent data lines; and
a resistive element provided between data lines connected to a same inspection-use display signal line.
The characteristics (d) includes:
a plurality of inspection-use scanning signal lines for supplying inspection-use scanning signals, the inspection-use scanning signal lines being provided for the plurality of scanning lines so that different scanning signals are inputted to adjacent scanning lines; and
a resistive element provided between scanning lines connected to a same inspection-use scanning signal line.
The data lines or scanning lines connected to the same resistive element are connected to the same inspection-use display signal line or the inspection-use scanning signal line. Therefore, while the resistive element maintains a structure for letting the static electricity escape, no current flows through the resistive element with no voltage applied thereto. Consequently, no voltage drop occurs in the inspection-use display signal line or the inspection-use scanning signal line, and the inspection efficiency is further improved.
An active-matrix-type liquid crystal display panel in accordance with another embodiment of the present invention is characterized in including:
(a) an active matrix substrate including on an insulating substrate: a plurality of pixel electrodes; pixel switching elements individually connected to the pixel electrodes; and a plurality of scanning lines and a plurality of data lines, provided in a lattice form, for driving the pixel electrodes through the pixel switching elements;
(b) an opposing substrate including a common electrode, the opposing substrate being adhered to the active matrix substrate with a liquid crystal layer therebetween;
characteristics (c) and/or characteristics (d).
The characteristics (c) includes:
data-line inspection-use switching elements, individually connected to the plurality of data lines, for controlling a supply of an inspection-use display signal;
a data-line inspection-use control signal line for inputting control signals for switching on/off the data-line inspection-use switching elements, the data-line inspection-use control signal line being a common data-line inspection-use control signal line provided for the data-line inspection-use switching elements;
a plurality of inspection-use display signal lines for supplying inspection-use display signals to the data lines through the data-line inspection-use switching elements, the plurality of inspection-use display signal lines being provided for the data-line inspection-use switching elements so that different display signals are inputted to adjacent data lines; and
a resistive element provided between data lines connected to a same inspection-use display signal line through the data-line inspection-use switching elements.
The characteristics (d) includes:
scanning-line inspection-use switching elements, individually connected to the plurality of scanning lines, for controlling a supply of an inspection-use scanning signal;
a scanning-line inspection-use control signal line for inputting control signals for switching on/off the scanning-line inspection-use switching elements, the scanning-line inspection-use control signal line being a common scanning-line inspection-use control signal line provided for the scanning-line inspection-use switching elements;
a plurality of inspection-use scanning signal lines for supplying inspection-use scanning signals to the scanning lines through the scanning-line inspection-use switching elements, the inspection-use scanning signal line being provided for the scanning-line inspection-use switching elements so that different scanning signals are inputted to adjacent scanning lines; and
a resistive element provided between scanning lines connected to a same inspection-use scanning signal line through the scanning-line inspection-use switching elements.
The data lines or scanning lines connected to the same resistive element are connected to the same inspection-use display signal line or the inspection-use scanning signal line. Therefore, while the resistive element maintains a structure for letting the static electricity escape, no current flows through the resistive element with no voltage applied thereto. Consequently, no voltage drop occurs in the inspection-use display signal line or the inspection-use scanning signal line, and the inspection efficiency is further improved.
In order to achieve the first object, a method of inspecting an active-matrix-type liquid crystal display panel in accordance with one embodiment of the present invention is a method of inspecting an active-matrix-type liquid crystal display panel including:
(a) an active matrix substrate having on an insulating substrate: a plurality of pixel electrodes; pixel switching elements individually connected to the pixel electrodes; and a plurality of scanning lines and a plurality of data lines, provided in a lattice form, for driving the pixel electrodes through the pixel switching elements;
(b) an opposing substrate having a common electrode, the opposing substrate being adhered to the active matrix substrate with a liquid crystal layer therebetween;
characteristics (c) and/or characteristics (d), and the method includes characteristics (e).
The characteristics (c) includes:
data-line inspection-use switching elements, individually connected to the plurality of data lines, for controlling a supply of an inspection-use display signal;
an inspection-use display signal line, provided for the data-line inspection-use switching elements, for supplying an inspection-use display signal to the data lines through the data-line inspection-use switching elements; and
a data-line inspection-use control signal line, provided for the data-line inspection-use switching elements, for inputting control signals for switching on/off the data-line inspection-use switching elements, the data-line inspection-use control signal line and the inspection-use display signal line having input terminals, the input terminals and an input terminal for inputting a signal to the common electrode in inspecting the liquid crystal display panel being located on a single side or opposing two sides of the active matrix substrate.
The characteristics (d) includes:
scanning-line inspection-use switching elements, individually connected to the plurality of scanning lines, for controlling a supply of an inspection-use scanning signal;
an inspection-use scanning signal line, provided for the scanning-line inspection-use switching elements, for supplying an inspection-use scanning signal to the scanning lines through the scanning-line inspection-use switching elements; and
a scanning-line inspection-use control signal line, provided for the scanning-line inspection-use switching elements, for inputting control signals for switching on/off the scanning-line inspection-use switching elements, the scanning-line inspection-use control signal line and the inspection-use scanning signal line having input terminals, the input terminals and an input terminal for inputting a signal to the common electrode in inspecting the liquid crystal display panel being located on a single side or opposing two sides of the active matrix substrate.
The characteristics (e) includes the step of inspecting a mother substrate by attaching an inspection-use jig thereto before dividing the mother substrate into individual pieces of active-matrix-type liquid crystal display panels, the mother substrate having the plurality of active-matrix-type liquid crystal display panels arranged in rows so that the input terminals of the plurality of active-matrix-type liquid crystal display panels are aligned in a direction of the single side.
Since the inspection can be performed for a mother substrate including a plurality of active-matrix-type liquid crystal display panels arranged in rows, the inspection efficiency is improved.
A method of inspecting an active-matrix-type liquid crystal display panel in accordance with another embodiment of the present invention is a method of inspecting an active-matrix-type liquid crystal display panel including:
(a) an active matrix substrate having on an insulating substrate: a plurality of pixel electrodes; pixel switching elements individually connected to the pixel electrodes; and a plurality of scanning lines and a plurality of data lines, provided in a lattice form, for driving the pixel electrodes through the pixel switching elements;
(b) an opposing substrate having a common electrode, the opposing substrate being adhered to the active matrix substrate with a liquid crystal layer therebetween;
characteristics (c) and/or characteristics (d), and the method includes characteristics (e).
The characteristics (c) includes:
data-line inspection-use switching elements, individually connected to the plurality of data lines, for controlling a supply of an inspection-use display signal;
an inspection-use display signal line, provided for the data-line inspection-use switching elements, for supplying an inspection-use display signal to the data lines through the data-line inspection-use switching elements; and
a data-line inspection-use control signal line, provided for the data-line inspection-use switching elements, for inputting control signals for switching on/off the data-line inspection-use switching elements.
The characteristics (d) includes:
scanning-line inspection-use switching elements, individually connected to the plurality of scanning lines, for controlling a supply of an inspection-use scanning signal;
an inspection-use scanning signal line, provided for the scanning-line inspection-use switching elements, for supplying an inspection-use scanning signal to the scanning lines through the scanning-line inspection-use switching elements; and
a scanning-line inspection-use control signal line, provided for the scanning-line inspection-use switching elements, for inputting control signals for switching on/off the scanning-line inspection-use switching elements.
The characteristics (e) includes the step of inspecting a mother substrate by attaching an inspection-use jig thereto before dividing the mother substrate into individual pieces of active-matrix-type liquid crystal display panels,
wherein the mother substrate is arranged so that the plurality of active-matrix-type liquid crystal display panels are arranged in rows, inspection-use wiring of a same kind in adjacent liquid crystal display panels are electrically connected to each other, and input terminals of the scanning-line inspection-use control signal line and the inspection-use scanning signal line and an input terminal for inputting a signal to the common electrode in inspecting the liquid crystal display panel are formed in an end section of the mother substrate with regard to a direction the liquid crystal display panels are connected, the end section belonging to none of the liquid crystal display panels.
Since the inspection can be performed for a mother substrate including a plurality of active-matrix-type liquid crystal display panels arranged in rows, the inspection efficiency is improved. In addition, even when the liquid crystal display panels to be detected are different in specifications such as the size, the inspection can be performed with a common inspection-use jig by forming the inspection-use input terminals at the same positions in the region. Therefore, it is favorable in the case where the volume of production is low and there are a wide variety of products to be made.
A method of inspecting an active-matrix-type liquid crystal display panel in accordance with another embodiment of the present invention is a method of inspecting an active-matrix-type liquid crystal display panel including:
(a) an active matrix substrate having on an insulating substrate: a plurality of pixel electrodes; pixel switching elements individually connected to the pixel electrodes; and a plurality of scanning lines and a plurality of data lines, provided in a lattice form, for driving the pixel electrodes through the pixel switching elements;
(b) an opposing substrate having a common electrode, the opposing substrate being adhered to the active matrix substrate with a liquid crystal layer therebetween;
characteristics (c) and/or characteristics (d), and the method includes the characteristics (e).
The characteristics (c) includes an inspection-use display signal line, provided for the plurality of data lines, for supplying an inspection-use display signal.
The characteristics (d) includes:
an inspection-use scanning display signal line, provided for the plurality of scanning lines, for supplying an inspection-use scanning signal.
The characteristics (e) includes the step of inspecting a mother substrate by attaching an inspection-use jig thereto before dividing the mother substrate into individual pieces of active-matrix-type liquid crystal display panels,
wherein the mother substrate is arranged so that a plurality of active-matrix-type liquid crystal display panels are arranged in rows in a direction of the scanning line, and a plurality of scanning lines in each liquid crystal display panel are connected to an inspection-use scanning signal line thereof via a region of an adjacent liquid crystal display panel.
Since the inspection can be performed for a mother substrate including a plurality of active-matrix-type liquid crystal display panels arranged in rows, the inspection efficiency is improved. After inspecting the liquid crystal display panel, the mother substrate is divided into individual panels. At this time, the data line (and/or the scanning line) in a first panel, which is connected to the inspection-use display signal line (and/or the inspection-use scanning signal line) in the first panel via an adjacent second panel, is divided. Therefore, the inspection-use switching elements become unnecessary for the data line (and/or the scanning line) to be divided, and it is favorable in reliability.
For a fuller understanding of the nature and advantages of the invention, reference should be made to the ensuing detailed description taken in conjunction with the accompanying drawings.